backus



Q. s. BACKUS.

CHUCK DRILL. I

Patented'Sept. 29, 1868.

gain]: giant ietsntffire.

QUIMBY S. BACKUS, OF'WI NGHENDON; MASSACHUSETTS.-

Letters Patent No. 82,583, dqted September 29,'1868.

IMPROVED CHUCK-DRILL.

TO ALL WHOM IT MAY CONCERN:

Be it known that I, QUIMBY S. BAOKUS, of Winchendon, in the county of Worcester, and State of Massachusetts, have invented certain Improvements in Chuck'-Drills, of which the'l ollcwing is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification, in which Figure 1 is a perspective view of my improved drill.

Figure 2 is a longitudinal section through the centre ofthe same.

FigureB is a transverse section on the'line a: :z of figs. land 2.

Figure 4 represents the point or end of the drill, in elevation. v

My invention relates to thatclass of drills, ordinarily termed chuck-drills, in which the drill, without revolving, is fed forward into the work, which latter'sim-ply revolveswithoutadvancing and my invention consists in a drill, having each of two ofits opposite sides provided with a-. gro ove, which inclines down to its point;

to allow the oil to flow thereto, and affords an unobstructed passage forthe chips or shavings to pass out, or the grooves may be straight and not inclined, while'the other two opposite sides of the drill are curved, and of uniform diameter throughout their length, the cutting-edges produced by the intersection of the grooves with the two opposite sides being so curvcd as to forma peculiar-shaped lip,'irhich, after entering the work, requiresf hut slight power to press it forward, by which construction I am enabled to bore-a true hole centrally into the work,- with the utmost facility-eon operation heretofore extremely difiicult to accomplish with drills of other forms.

To enable others skilled in the art to understand and use my invention, I will proceed to describe the manner in which I have carried it out In the saiddrawings, A represents my improvedchuck-drill, with each of-two of its opposite sides provided with a groove, a, which inclines from near the back of the drill at 5 to the point" 6, in order to allow the lubricating-material to flow down thereto, and forms a channel, by which the chips are free to pass out of the hole being bored in the work. The other two oppositesidesor surfaces 6 are curved outward in transverse section, the degree-of curvatarccorresponding to the circumference of the hole of the size to bc bored.

Tllc diameter or width of the driil between the sides 6 is the same throughout its length, excepting from its point b, to the intersections of these sides with the grooves a, which thus form the cutting-edgesc, the curvature of which is such that after they enter the revolving work, while being bored, the body of the'dri'll is advanced rapidly, and with the expenditure of but little power, forming for itself a snug hearing against the side or periphery of the hole, which thus 'prevents it.from having any lateral play therein; the form and relation 0f the grooves a and sides 5 also serving to stiffen and strengthen the drill, and prevent it from springing while advancing. I

'lfheinclination of each of the cutting-edges c from 6 to 7 is about forty-five degrees, and the peculiar shape of the lip thus formed, admits of its being conveniently sharpened. By thus making the drill, throughout its length, of the same diameter between its two opposite sides Z1, a

hole bored by it is made perfectly true, and in a line with the exact centre or axis of thc'article being bored,

and the drill is worn away uniformly, so as to admit of its being used when quite short, as well as when of its original length.

. Claim.

What I claim as my invention, and desire to secure by Letters Patent, is- The within-described chuck-drill, constructed to operate substantially as set forth. 7 I I QU IMBY s. BAGKUS.

Witnesses:

N. W. STEARNS, W. J. Cmsnmcs. 

